2-phenyl-4-acyl-(3H)-pyrazol-3-ones

ABSTRACT

Liquid/liquid extraction process for copper from an aqueous sulphuric acid solution acting on the concentrated mineral or semi-finished product to be treated. 
     The extraction is carried out in an organic solvent containing in solution an extraction agent derived from 2-phenyl-4-acyl-(3H)-pyrazol-3-ones, with the phenyl group substituted or unsubstituted. 
     Application to the upgrading of minerals.

This is a divisional of application Ser. No. 593,863, filed Mar. 27,1984, now U.S. Pat. No. 4,666,513.

This invention concerns the selective extraction of copper.

More specifically the invention concerns the selective extraction ofcopper from concentrated minerals or semi-finished products containingit, using a liquid/liquid extraction technique.

Over the last twenty years much research has been carried out onupgrading more and more impoverished minerals (with approximately 1%copper), difficult to concentrate or too complex to be treated using theclassical methods of pyrometallurgy.

The development of extraction agents (hereafter called extractants) forcopper with high extractive power has made it possible to developsolvent extraction techniques.

Several families of organic extractants have been proposed in order toconcentrate leaching solutions by liquid/liquid extraction. The bestknown of these are chelating agents of the hydroxyl oxime type, amongstwhich to be specially recommended are those put on the market by GeneralMills under the generic heading of the LIX series and those marketed byShell under the designation SME 529 and by ICI under the designationACORGA P 5000 or chelating agents of the hydroxyquinoline type such asthose marketed by Ashland Chemical under the designations KELEX 100 andKELEX 120.

At present 15% of the world's production of copper, viz 1.2 milliontonnes is obtained by hydrometallurgy with the help of these extractionagents. Extraction on an industrial scale is then mainly carried outfrom sulphuric acid solutions of the mineral by means of extractantsdissolved in organic diluting agents such as aliphatic or aromatichydrocarbons with a high flash point such as the kerosines, the naphthasand similar compounds. Mention can be made of SOLVESSO 150 and ESCAID100 manufactured by ESSO among the most used of the commercial products.

The disadvantages of extractants in current use are essentially thefollowing:

(1) The extractants of the LIX series, in particular LIX 64N which isthe most developed product of this series have:

(a) a low copper extractive power despite very good selectivity withrespect to Ni and Co which makes it necessary to work with organic phaseand aqueous phase volumes with a high ratio or with an extremely highconcentration of extractant; in either case the result is that a higherinvestment has to be made than normal either for the extractioninstallation or for the extractant to be used, with still in the finalanalysis a result which is inadequate.

(b) a slight concomittant extraction of iron which makes it necessary toretreat the aqueous reextraction solution before the electrolysis phasewhich is the classical phase for purifying the extracted metal.

(c) the necessity of operating at temperatures below 40° C. since LIX64N contains 1% LIX 63 which is unstable above this temperature.

(2) For other extractants with similar structure such as the productwith the commercial name SME 529 and the products of the ACORGA series(see above):

(a) although they give higher extraction coefficients than the productsof the LIX series and have better extraction and reextraction kineticsthey still make reextraction very difficult so that the residual levelof copper in the aqueous phase is too high (see J. A. Tumilty, Advancein extractive metallurgy, 1977, p. 123).

(b) it is therefore necessary to add quite significant amounts of amodifier (in practice 4-nonylphenol). However, the improvement inreextraction which is likely to result has a low coefficient ofextraction.

(3) For extractants of the KELEX type, in particular KELEX 100, used forsulphide minerals which give solutions more concentrated in copper (ofthe order 30-50 g/l), 4-nonylphenol is added to prevent the formation ofa third phase.

Work carried out in recent years on the extraction of nonferrous metals,essentially copper, in a sulphuric acid medium, has thus been mainlyconcerned with tests aimed at improving existing systems and overcomingin some way or other the known disadvantages of these systems. In thisway additives to such systems have been tested aimed at:

(a) either improving the performances of the main extractant from thepoint of view of extractive power, selectivity and extraction kinetics,

(b) or preventing the formation of a precipitate at the interface or theformation of a third phase.

On the other hand patent No. DD-A-142.059 describes a process forrecovering metals, more specifically lead, zinc and copper withoutselectivity by leaching complex minerals by means of a solution ofextraction agents chosen from complexing agents of the polydentate type,dissolved in organic solvents such as dialkyldithiophosphoric acids,4-acyl-pyrazolones or dithiocarbamates dissolved in chlorinatedhydrocarbons, aliphatic or aromatic hydrocarbons, alcohols or ketones.

In this process the minerals are not first treated with alkaline oracidic solutions.

This is not a liquid/liquid extraction but an attack on the crushedmineral by an organic solution of a complexing agent and then afterseparation of the solid residue, extraction of the metals from the saidorganic solution by means of a solution of a dilute (2N) mineral acid.This process leads to a nonselective extraction and makes it necessaryto have an additional retreatment stage so that each of the metalsextracted together can be obtained pure.

The aim of this invention is the selective extraction of copper with ahigh yield from concentrated minerals or semi-finished productscontaining it by a liquid/liquid extraction technique.

The problem put in this way is solved by a liquid/liquid extractionprocess involving first reacting the concentrated mineral orsemi-finished product with an acidic leaching agent in an aqueousmedium, preferably sulphuric acid, and according to which the copper isextracted from the reaction solution by a liquid/liquid extraction usingat least one appropriate 2-phenyl-4-acyl-5-alkyl(orphenyl)-(3H)-pyrazol-3-one in organic solution, the phenyl groups beingpossibly substituted by alkyl groups.

The process conforming to the invention has proved unexpectedly capableof providing quite exceptional extraction selectivity with respect toiron and extraction yield of copper, better extractive power than thatof classical techniques, greater ease of operation and lower cost inview of the possibility of avoiding or at least cutting down theaddition of modifiers such as nonylphenol which was indispensable uptill now.

It has been found according to the invention that these results as wellas others which follow in this text are obtained thanks to a processwhich constitutes the primary object of this invention and according towhich a liquid/liquid extraction is carried out on copper from anaqueous sulphuric acid solution acting on the concentrated mineral orsemiproduct to be treated using at least one extraction agent of thetype 2-phenyl-4-acyl-5-alkyl-(or phenyl)-(3H)-pyrazol-3-one in anorganic solvent suitable for diluting and dissolving this extractionagent and as much as possible the complex which the latter forms withthe copper to be extracted.

More specifically the useful extraction agent conforming to theinvention corresponds to the formula: ##STR1##

This β-dicarbonyl compound can just as well exist in one of the twoketo-enol forms: ##STR2##

where R₁ represents a phenyl group, possibly substituted by one orseveral alkyl groups containing 1-12 carbon atoms

where R₂ represents a branched or straight-chain alkyl group containing1-12 carbon atoms or a phenyl group possibly substituted by 1 or severalalkyl groups each containing 1-12 carbon atoms

where Z represents a straight-chain or branched, saturated orunsaturated alkylene group containing 1-21 carbon atoms

and where R₃ represents H, a(2-phenyl-5-alkyl-(3H)-pyrazolyl-3-one)-carbonyl-4 or a(2-phenyl-5-phenyl-(3H)-pyrazolyl-3-one)-carbonyl-4 thus forming a bisacylpyrazolone with the formula: ##STR3## wherein the phenyl groups mayor may not be substituted by alkyl groups.

According to an advantageous form of the invention R₁ represents thephenyl group and R₂ an alkyl group with 1-5 carbon atoms preferably themethyl group; according to another advantageous form of the invention,R₁ represents a phenyl group substituted by an alkyl group with 8-12carbon atoms.

Finally Z preferably represents an alkylene group with 6-17 carbonatoms, more specifically ethyl-1-pentylene, undecylene or heptadecylenewith R₃ =H and a --(CH₂)₄ -- group when R₃ represents apyrazolylcarbonyl as defined above.

For greater clarity it should be pointed out that here it has beendecided to designate these products as being derivatives of4-acyl-(3H)-pyrazol-3-ones, this practically conforming to the officialnomenclature in force since 1972 whereas the nomenclature in use beforethis date assigned the designation 4-acyl-2-pyrazolin-5-ones to productsof this type. It is obvious that these are the same products.

Some of the compounds are new.

Thus the object of the invention is also the new products falling withinthe framework of the above-mentioned formula, more specifically thefollowing:

(a) 2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one

(b) 2-phenyl-4-isononanoyl-5-methyl-(3H)-pyrazol-3-one

(c) di-1,6-(2-phenyl-5-methyl-4-pyrazolyl-3-one)-hexan-1,6-dione

(d) 2-phenyl-4-undecenoyl-5-methyl-(3H)-pyrazol-3-one

(e) 2-phenyl-4-oleoyl-5-phenyl-(3H)-pyrazol-3-one

(f) di-1,10-(2-phenyl-5-phenyl-4-pyrazolyl-3-one)-decan-1,10-dione.

These compounds may be prepared from known products by techniques knownto those in the field such as the method described by Jensen in ActaChemica Scandinavica, 13, 1668 (1959) according to which the acidchloride with formula H--Z--COCl in the case of the monopyrazolones orClOCZCOCl in the case of the dipyrazolones is made to react with theheterocylic compound, unsubstituted at position 4 in the presence ofcalcium hydroxide.

According to the invention an organic solvent is used to dilute anddissolve the extraction agent and the complex which the latter formswith copper; it must be practically insoluble in water and not disturbthe action of the extraction agent. This organic solvent shouldpreferably have a high flash point.

Generally it is advisable that the organic solvent can dissolveapproximately 20-750 g/l and preferably approximately 50-200 g/l of theextraction agent.

Efficient organic solvents are aliphatic or aromatic hydrocarbons with ahigh flash point such as the kerosines, naphthas and similar compounds.

Amongst these solvents, the products available on the market under thename SOLVESSO and distributed by ESSO are very strongly recommended,especially the product corresponding to the trade name SOLVESSO 150which is an aromatic petroleum solvent.

The extraction process according to the invention is carried out byputting the organic solvent containing the extraction agent in contactwith the aqueous solution of the leaching agent containing the copperand other metal entities resulting from the action on the mineral. Theleaching agent is preferably sulphuric acid. The two phases, the aqueousphase and the organic phase, can be put in contact by extractiontechniques well known to those working in this field (continuous ordiscontinuous extraction, use of mixer-settlers or extraction columns,etc. . . . ; countercurrent techniques should be preferably used forcirculating the fluids).

The ratio of the volumes of the aqueous and organic phases depends onthe apparatus used, the concentration of the extraction agent in theorganic phase and the composition of the aqueous phase to be treated. AV_(aq) /V_(org) ratio lying between approximately 3/1 and 1/3 isdesirable.

The temperature at which the phases are put into contact and areseparated is not a key factor; it is simply related to the flash pointof the solvent used; a temperature between 20° and 60° C. is advisablein practice.

It seems that with certain acylpyrazolones recommended by the inventionthe complex formed between the copper and the extraction agent may beprecipitated after a certain lapse of time. It has been found, and thisconstitutes an alternative process according to the invention, that thisprecipitation can be delayed without however inhibiting the action ofthe agent by adding approximately 2-20% by volume and preferably 10% byvolume of 4-nonylphenol or an equivalent to the solution of theextraction agent in the organic solvent.

The aqueous phase undergoing the process according to the invention maybelong to two different types; in fact, depending on the nature of theminerals or mineral concentrates and specifically the nature of thecopper minerals to be treated, a distinction is made between two typesof sulphuric acid solutions for extracting copper using hydrometallurgy:

(a) sulphuric acid solutions formed from oxide minerals with a lowconcentration of copper (1-10 g/l) containing iron, cobalt and nickelwith variable contents and with pH lying between 1 and 3;

(b) sulphuric acid solutions formed from sulphide minerals with a highconcentration of copper (15-40 g/l) also containing high concentrationsof iron, nickel and cobalt and with pH lying between 1 and 3.

The solutions would be less stable at higher pH values; the extractioncoefficient would be lower at lower pH values.

The invention is illustrated more specifically below, referring topreferred forms of implementation and to non-exhaustive examples ofapplication.

The extraction characteristics of the products recommended by theinvention have been compared with those of products currently used inindustry for the same purposes viz: LIX 64N (which contains 1% LIX 63)##STR4## for aqueous sulphuric acid solutions with a low copper content(approximately 3 g/l);

KELEX 100 ##STR5## for aqueous sulphuric acid solutions with a highcopper content formed from copper sulphide minerals.

The corresponding comparative extraction tests have been carried out onsynthetic solutions representative of industrial compositions normallytreated and shown below:

    ______________________________________                                        Composition of the solutions                                                  representative of minerals                                                                      representative of sulphide                                  with low Cu content =                                                                           minerals =                                                  aqueous phase type A                                                                            aqueous phase type B                                        ______________________________________                                        H.sub.2 SO.sub.4                                                                      dilute        H.sub.2 SO.sub.4                                                                        dilute                                        Cu      3 g/l         Cu        23 g/l                                        Fe      3 g/l         Fe         6 g/l                                                              Ni        18 g/l                                                              Co         1 g/l                                        (amount of H.sub.2 SO.sub.4 sufficient                                                          (amount of H.sub.2 SO.sub.4 sufficient                      for pH = 1 and 2.5)                                                                             for pH = 1 and 2)                                           ______________________________________                                    

Based on a preliminary study on the possible diluents satisfying thedefinition given above preference was given to the aromatic petroleumsolvent marketed under the name SOLVESSO 150.

As an alternative, finding its use essentially in those cases where itis necessary to prevent the formation of a more or less significantprecipitate in the organic phase (usually occurring after several hours,for example after 12-24 hours), it has been advantageous to also addapproximately 2-20%, preferably approximately 10% nonylphenol by volumeto the organic extraction phase.

The other tests which have been carried out are referred to hereafter byreference to the figures of drawings, of these:

FIG. 1 represents the effect of the concentration of the extractionagent 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150plotted along the x-axis as well as that of the pH of the aqueous phaseto be treated (aqueous phase type A) on the extraction (% Cu extractedplotted along the y-axis);

FIG. 2 represents the extraction isotherms obtained by treating anaqueous sulphuric acid solution type A at pH 2.5;

(1) For the dotted line curve, with the commercial product LIX 64N at aconcentration of 15% in the diluent marketed under the name ESCAID 100;

(2) For the unbroken line curve, with2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one at a concentration of 50g/l in SOLVESSO 150+10 ml/100 ml volume of nonylphenol.

FIGS. 3 and 4 represent the reextraction isotherms obtained fromsuccessive contact between the same sulphuric acid aqueous phase anddifferent organic phases containing copper.

In the case of FIG. 3 the aqueous phase does not contain copper at thebeginning.

In the case of FIG. 4 the initial concentration of copper in the aqueousphase is 30 g/l which simulates an aqueous phase at the output of thecopper electrolysis circuit, recycled as an aqueous stripping solution,i.e. used to reextract the copper contained in the organic phase. Thecopper-bearing organic phase contains, in the examples of FIG. 3, theextraction agent2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one (curve 3), LIX64N (curve 1) an 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one (curve2) and in the examples of FIG. 4 the extraction agent2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one (curve 2) andLIX 64N (curve 1).

These tests whose results are given in the above-mentioned figures (towhich it is worth referring) show that:

1. As far as the optimum concentration of the extraction agent and thepH of the aqueous phase best suited for obtaining maximum extraction areconcerned:

in the case of a solution with low copper content:

at pH 2.5 it is not necessary to use concentrations higher than 50 g/lin order to exhaust the aqueous phases with a limited number of stages,

in comparison with the commercial extraction agent LIX 64N, theperformance of 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one dissolvedin SOLVESSO (concentration 50 g/l) is equivalent to that of LIX 64N at aconcentration of 136 g/l in the diluent ESCAID 100 (refer to table I andto the corresponding curves of FIG. 2).

in the case of an aqueous sulphuric acid solution with a high coppercontent compared to KELEX 100 at a concentration of 15% by volume (i.e.143 g/l) in SOLVESSO 150 with the addition of 20% nonylphenol, theperformance of the acylpyrazolones(2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one and2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one) is of the sameorder of magnitude at an equivalent concentration and even at a slightlylower concentration (i.e. 120-130 g/l).

(See table II and FIG. 3 curve 1 for LIX, curve 2 for lauroylpyrazoloneand curve 3 for hexanoylpyrazolone).

2. The extraction isotherms plotted so that the saturation capacity ofthe extraction agent can be revealed (see FIG. 2) are practicallyindistinguishable for 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one andLIX 64N which confirms the equivalent performance of "lauroylpyrazolone"at a concentration of only 50 g/l and LIX 64N with a concentration of15% by volume, i.e. 136 g/l.

The tests which have been carried out make it possible to calculate thefollowing extractive powers:

    ______________________________________                                                                   relative efficacy of                                            mg of copper per g                                                                          the pyrazolones and                                extractant   of extraction agent                                                                         LIX 64 N                                           ______________________________________                                        4-lauroyl-P  80            2.66                                               4-stearoyl-P 70            2.33                                               4-(2-ethyl)hexanoyl-P                                                                      90            2.83                                               4-nonanoyl-P 104           3.46                                               LIX 64 N     30            1                                                  ______________________________________                                         P = 2phenyl-5-methyl-(3H)--pyrazol3-one                                  

It can be concluded that for an equivalent amount, the2-phenyl-4-acyl-5-methyl-(3H)-pyrazol-3-ones have an extractive powerapproximately 3 times higher than that of LIX 64N.

3. The isotherm reextraction curves obtained for the comparativereextraction tests with successive contact of the same aqueous sulphuricacid phase with different organic phases containing extractable metalentities are linear which proves that saturation of the aqueous phasehas not been reached (FIGS. 3 and 4).

The isotherms for 2-phenyl-4-lauroyl-5-methyl-pyrazol-3-one and theproduct of the LIX type lie close to each other.

Reextraction is slightly easier in the case of2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one. FIG. 4 showsparticularly clearly in a representative case of industrial conditions(aqueous phase initially containing copper) that the reextraction ofcopper is more efficient in the case of2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one than in thecase of LIX 64N.

On the other hand, as far as the extraction selectivity is concerned,i.e. the separation of Cu and of the other metals Fe, Ni, Co thequantitative analysis made on the raffinate (exhausted aqueous phase)and on the organic phase (the results of which can be seen from tablesI, II and IV below) has shown that the selectivity is better for a largemajority of the products according to the invention than using thecommercial products LIX 64N or KELEX 200 as extractants.

In particular table IV contains the results of calculating the Cu/Feselectivity after 10 minutes of extraction. This selectivity is equal tothe ratio of the partition coefficients: ##EQU1## where [M]_(org)represents the concentration of the metal M in the organic phase, and[M]_(aq) represents the concentration of the metal M in the aqueousphase. Since the concentrations of iron and copper are initially thesame another method of expressing the selectivity is to take the ratio[Cu]_(org) :[Fe]_(org).

This selectivity is confirmed by the quantitative analysis results foriron and copper in aqueous solutions resulting from sulphuric acidreextraction (1N H₂ SO₄) (table III below) and by the quantitativeanalysis results for the same elements in the corresponding organicphase.

In fact, in the presence of acylpyrazolone, 10 times less iron isextracted than in the presence of LIX 64N while the amounts of copperextracted are practically the same.

The selectivity with respect to nickel and cobalt is even better. Infact, these metals are not extracted by2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one dissolved in SOLVESSO 150(40 g/l) from an aqueous sulphuric acid solution in which they arepresent at a concentration of approximately 3 g/l.

This selectivity is again confirmed by the results of treating asulphuric acid solution with a high copper content (23 g/l), alsocontaining 6 g/l Fe, 18 g/l Ni and 1 g/l Co with2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one in the diluentSOLVESSO 150 at a concentration of 0.42 moles per liter.

The bearing organic phase contained (see example 10 below):

    ______________________________________                                        Cu    8         g/l      i.e.                                                                              34.8%   extraction                               Ni    0.15      g/l      i.e.                                                                              0.8%    extraction                               Co    <0.001    g/l      i.e.                                                                              <0.1%   extraction                               Fe    0.06      g/l      i.e.                                                                              <1%     extraction                               ______________________________________                                    

Example 11 below concerns a comparison between2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one and the commercialproduct called KELEX 100 and again shows the superior selection obtainedin the extraction of Cu in the presence of iron, nickel and cobalt withpyrazolone according to the invention.

The invention is illustrated in detail in the following examples whichdo not limit it in any way.

EXAMPLE 1

Extraction of copper from low-concentration solutions thereof at pH 2.5by 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution at pH 2.5 containing 2.9 g/l copper(Cu²⁺) and 3.2 g/l iron is put in contact with a solution of2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one is SOLVESSO 150 at aconcentration of 100 g/l without an additive of the nonylphenol type.

The extraction is carried out volume by volume in a separating funnel at20° C. with mechanical shaking for 1/2 hour. The pH of the aqueoussolution at equilibrium is then measured.

After decantation the contents of copper and iron in the residualaqueous phase (the so-called raffinate) are measured by atomicabsorption. The contents of the metals in the organic phase arecalculated by difference.

The results obtained are the following:

pH at equilibrium: 1.4

Cu extracted: 99.7% of the initial Cu

Fe extracted: approximately 3% of the initial Fe.

EXAMPLE 2

Extraction of copper from low-concentration solutions at pH=1 by2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 1 containing 2.9 g/l copper(Cu²⁺) and 3.2 g/l iron is put in contact, volume by volume, with asolution of 100 g/l 2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one inSOLVESSO 150 without adding nonylphenol.

The extraction and analysis are carried out as in example 1.

The results are as follows:

pH at equilibrium: 0.8

Cu extracted: 85.3% of the initial Cu

Fe extracted: approximately 0%.

EXAMPLE 3

Extraction of copper from a low-concentration solution with pH 2.5 by2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.5 containing 3 g/l copper(Cu²⁺) and 3.2 g/l iron is put in contact, volume by volume, with asolution of 42 g/l2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one in SOLVESSO150.

The extraction and analysis are carried out as in example 1.

The results are as follows:

pH at equilibrium: 1.5

Cu extracted: 82% of the initial Cu

Fe extracted: approximately 0%.

EXAMPLE 4

Extraction of copper from a low-concentration solution at pH=2.5 by2-phenyl-4-stearoyl-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution at pH 2.5 containing 2.9 g/l copper(Cu²⁺) and 3.2 g/l iron is put in contact, volume by volume, with asolution of 62 g/l 2-phenyl-4-stearoyl-5-methyl-(3H)-pyrazol-3-one inSOLVESSO 150 with 10 ml/100 ml nonylphenol.

The extraction and the analysis are carried out as in example No. 1.

The results are as follows:

pH at equilibrium: 1.7

Cu extracted: 89.6% of the initial Cu

Fe extracted: approximately 0%

EXAMPLE 5

Extraction of copper from a low-concentration solution with pH 2.3 by2,5-diphenyl-4-oleoyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.3 containing 3.2 g/l copper(Cu²⁺) and 3.35 g/l iron is put in contact, volume by volume, with asolution of 50 g/l 2,5-diphenyl-4-oleoyl-(3H)-pyrazol-3-one in SOLVESSO150.

The extraction is carried out as in example 1. The quantitative analysisis made by measuring the contents of copper and iron by atomicabsorption in the aqueous and organic phases.

pH at equilibrium: 1.4

Cu extracted: 68% of the initial Cu

Fe extracted: 0.3% of the initial Fe.

EXAMPLE 6

Extraction of copper from a low-concentration solution at pH 2.3 by2-phenyl-4-undecenoyl-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.3 containing 3.13 g/lcopper (Cu²⁺) and 3.21 g/l iron is put in contact, volume by volume,with a solution of 50 g/l2-phenyl-4-undecenoyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150 with10% volume by volume nonylphenol.

The extraction and analysis are made as in example No. 5.

pH at equilibrium: 1.4

Cu extracted: 68% of the initial Cu

Fe extracted: 1.4% of the initial Fe

EXAMPLE 7

Extraction of copper from a low-concentration solution at pH 2.3 by2-phenyl-4-lauroyl-5-(n-propyl)-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.3 containing 3.13 g/lcopper (Cu²⁺) and 3.21 g/l iron is put in contact, volume by volume,with a solution of 50 g/l2-phenyl-4-lauroyl-5-(n-propyl)-(3H)-pyrazol-3-one in SOLVESSO with 10%volume by volume nonylphenol.

The extraction and analysis are carried out as in example 5.

pH at equilibrium: 1.45

Cu extracted: 66% of initial Cu

Fe extracted: 0.6% of initial Fe.

EXAMPLE 8

Extraction of copper from a low-concentration solution with pH 2.5 by2,5-diphenyl-4-lauroyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.5 containing 3 g/l copper(Cu²⁺) and 3 g/l iron is put in contact for 1/2 hour, volume by volume,with a 0.14M solution (50.6 g/l) of2,5-diphenyl-4-lauroyl-(3H)-pyrazol-3-one in SOLVESSO 150 with 10%nonylphenol volume by volume.

The extraction and the analysis are carried out as in example No. 5.

pH at equilibrium: 1.4

Cu extracted: 76% of the initial Cu

Fe extracted: 0.7% of the initial Fe.

EXAMPLE 9

Extraction of copper from a medium-concentration solution with pH 2.3 by2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2.3 containing 6.16 g/lcopper (Cu²⁺) and 1.24 g/l iron is put in contact for 1/2 hour, volumeby volume, with a solution of 100 g/l2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150with 2% nonylphenol (volume by volume).

The extraction and the analysis are carried out as in example No. 5.

pH at equilibrium: 1.4

Cu extracted: 76% of the initial Cu

Fe extracted: 1.2% of the initial Fe

EXAMPLE 10

Extraction of copper from a high-concentration solution with pH=2 by2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2 containing 23 g/l copper, 6g/l iron, 18 g/l nickel and 1 g/l cobalt is put in contact with asolution of 126 g/l2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one in SOLVESSO150.

The extraction is carried out in a separating funnel with mechanicalshaking for 1/2 hour. The elements are analysed by atomic absorptioneither in the residual aqueous phase (raffinate) or in a reextractionaqueous phase (1N H₂ SO₄) in order to increase the measuringsensitivity.

The results are as follows:

Cu extracted: 34.8% of the initial Cu

Ni extracted: 0.8% of the initial Ni

Fe extracted: 1% of the initial Fe

Co extracted: 0.1% of the initial Co

EXAMPLE 11

Extraction of copper from a high-concentration solution with pH 2 by2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

An aqueous sulphuric acid solution with pH 2 containing 22.6 g/l copper,6.1 g/l iron, 19.2 g/l nickel and 0.8 g/l cobalt is put in contact,volume by volume, at 20° C. with a solution of 150 g/l2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150.

The extraction is carried out in a separating funnel with shaking for1/2 hour. The elements are analysed by atomic absorption in the residualaqueous phase (raffinate) and the extraction rates evaluated bysubtraction.

The results are as follows:

final pH at equilibrium: 0.9

Cu extracted: 54.9% of the initial Cu

Fe extracted: 2.1% of the initial Fe

Ni extracted: 1.6% of the initial Ni

Co extracted: 2.5% of the initial Co.

By way of comparison extraction of the same acid solution by 143 g/lKELEX 100 in SOLVESSO 150 (with 20 ml/100 ml nonylphenol) gives thefollowing results:

final pH at equilibrium: 1.1

Cu extracted: 45.3% initial Cu

Fe extracted: 4.8% initial Fe

Ni extracted: 2.7% initial Ni

Co extracted: 3.7% initial Co.

EXAMPLE 12

Extractive power of 2-phenyl-4-acyl-5-methyl-(3H)-pyrazol-3-ones.

The extraction isotherms are obtained by successive contact of the sameorganic phase with a new aqueous phase under the following conditions:

Aqueous phase: sulphuric acid solution with pH 2.5 containing 3 g/lcopper and 3 g/l iron.

Initial organic phase consists of 50 g/l of the acyl pyrazolonedissolved in SOLVESSO 150 with 10 ml/100 ml nonylphenol (except for2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one wherenonylphenol is not added).

The extractions are carried out volume by volume at 20° C. in separatingfunnels with a contact of 1/2 hour with shaking in each case. The copperis analysed by atomic absorption in the residual aqueous phases(raffinate) and the copper concentration in the organic phases evaluatedby subtraction.

The extractive power of the extractant at saturation is calculated fromthe extraction isotherms by dividing the maximum metal concentration (ing metal per liter) determined from the isotherm by the concentration ofextractant which is assumed to be pure expressed in g/l.

2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one gives:

80 mg Cu/g extractant;

2-phenyl-4-stearoyl-5-methyl-(3H)-pyrazol-3-one gives:

70 mg Cu/g extractant;

2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one gives:

90 mg Cu/g extractant;

2-phenyl-4-isononanoyl-5-methyl-(3H)-pyrazol-3-one gives:

104 mg Cu/g.

By way of comparison the extractive power of LIX 64N at a concentrationof 136 g/l in ESCAID 100 is 30 mg Cu/g extractant.

EXAMPLE 13

Reextraction in the case of2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

Reextraction has been carried out under the following conditions:reextraction isotherms were obtained by successive contact of the sameaqueous H₂ SO₄ phase (1N) with a new organic phase containing 50 g/l2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150containing 10 ml/100 ml nonylphenol and 4 g/l copper; equilibriumcorresponding to the lowest concentrations is obtained by exhausting theorganic phase resulting from the first contact with a fresh aqueousphase.

The contacts are made in separating funnels at 20° C. for 1/2 hour. Theconcentrations are determined by atomic absorption in the aqueous phasesand organic phases at the same time (after dilution in ethanol in thelatter case). The extraction isotherms are collected together in FIG. 3where curve 1 refers to LIX 64N at a concentration of 136 g/l in ESCAID100 and curve 2 refers to2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

EXAMPLE 14

Reextraction in the case of2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

The same procedure as that of example 13 was followed. The reextractionisotherm was obtained from results of successive contact (volume byvolume) of the same aqueous phase (1N H₂ SO₄) with a new organic phasecontaining the extractant at a concentration of 0.14 mole/l i.e. 42 g/land copper at a concentration of 3.3 g/l in SOLVESSO 150 without anynonylphenol.

The contacts took place in a separating funnel while shaking for 1/2hour at ambient temperature.

The copper and iron were analysed by atomic absorption in the aqueousreextraction phases.

The plotted isotherm is linear and gives slightly higher values thanthose obtained with LIX 64N and2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one (FIG. 3 curve 3).

EXAMPLE 15

Reextraction by an aqueous stripping solution with 30 g/l copper. Caseof 2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

Reextraction was carried out under the following conditions: thereextraction isotherms are determined by successive contact of the sameorganic phase (3N H₂ SO₄, 30 g/l Cu) with a new organic phase containing50 g/l 2-phenyl-4-(2-ethylhexanoyl)-5-methyl-((3H)-pyrazol-3-one inSOLVESSO 150 containing 10 ml/100 ml nonylphenol and 3.5 g/l Cu.

The contacts take place in a separating funnel at 20° C. for 1/2 hour.The concentrations are determined by atomic absorption at the same timein the aqueous phases and organic phases (after dilution in ethanol forthe latter cases). The extraction isotherms are collected together inFIG. 4 where curve 1 refers to LIX 64N (at a concentration of 15% inESCAID 100) and curve 2 refers to2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

EXAMPLE 16

Copper/iron selectivity.

Copper/iron selectivity has been studied by analysing the iron in 1N H₂SO₄ reextraction solutions obtained as described in example 13, theinitial aqueous solution having a low copper concentration at pH 2.5with 3 g/l copper and 3 g/l iron.

The following results are obtained for the final solutions most enrichedin copper:

2-phenyl-4-lauroyl-5-methyl-(3H)-pyrazol-3-one

Cu: 11.9 g/l

Fe: 0.032 g/l

2 phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one

Cu: 11.5 g/l

Fe: <0.01 g/l

LIX 64N

Cu: 13.8 g/l

Fe: 0.310 g/l

EXAMPLE 17

Extraction of copper and iron by the 4-acyl-(3H)-pyrazol-3-ones.Comparative selectivity.

All the 4-acyl-(3H)-pyrazol-3-ones have been studied using the sameprocedure:

The aqueous solution of copper sulphate with 3 g/l copper (Cu²⁺) andiron sulphate with 3 g/l iron is adjusted to pH 2.5 by adding H₂ SO₄under potentiometric control.

50 ml of this solution are poured into a cell with temperaturecontrolled at 25° C. and equipped with a magnetic stirrer. 50 ml of theorganic extraction phase (0.14 moles 4-acyl-(3H)-pyrazol-3-one inSOLVESSO 150 with or without depending on the case 10% nonylphenol byvolume) are slowly added to this solution avoiding any agitation.

Finally the magnetic stirrer is set to 750 rpm and started.

Intermediate samples are taken in the aqueous and organic phases attimes of 3, 10 and 60 minutes in order to measure the amount ofextracted iron and copper by atomic absorption.

The results are collected in table IV expressed as an extractionpercentage with respect to the amount initially present in the aqueoussolution.

EXAMPLE 18

Preparation of 2-phenyl-4-(2-ethylhexanoyl)-5-methyl-(3H)-pyrazol-3-one.

A mixture of 1044 g (6 moles) of 2-phenyl-5-methyl-(3H)-pyrazol-3-oneare stirred in 4 liters of dioxan and the temperature brought to 60° C.in order to completely dissolve the pyrazolone. 888 g (12 moles) ofcalcium hydroxide Ca(OH)₂ are then added and then for 45 minutes 876 g(5.4 moles) of 2-ethylhexanoyl chloride. The temperature of the mixturereaches 95° C. and the mixture is kept at this temperature understirring for 2 hours.

After cooling the reaction mixture is poured into 8 liters HCl (2N). Anorganic layer separates and 2 liters of toluene are added in order tofacilitate decantation; The organic phase is dried over magnesiumsulphate and the solvent eliminated under reduced pressure.

The oily residue obtained with a yield of 77% is rectified in a vacuumdistillation apparatus and using a thin film technique. The productdistils at 162° C. under 0.1 Pa.

The yield of purified product is 61%.

Indentification has been carried out

(1) by NMR (proton)

The NMR spectrum taken in CDCl₃ as solvent and TMS as reference exhibitsthe following peaks:

at 2.5 ppm: singlet corresponding to the CH₃ at position 5 on thepyrazole ring,

between 0.7 and 3.1 ppm: multiplets attributed to the alkyl residue,

between 7.2 and 8 ppm: multiplets of the aromatic ring,

at 14 ppm: singlet corresponding to the enol proton.

(2) by elementary analysis

    ______________________________________                                                    C        H       N                                                ______________________________________                                        experimental values:                                                                        71.97%     8.39%   9.32%                                        theoretical values:                                                                         71.93%     8.00%   9.46%                                        ______________________________________                                    

(3) refractive index n_(d) ²⁰ =1.5560

(4) density at 20° C.=1.0678.

EXAMPLE 19

Preparation of 2-phenyl-4-isononanoyl-5-methyl-(3H)-pyrazol-3-one.

Following the procedure of example 18 with the same proportionsreplacing 2-ethylhexanoyl chloride by isononanoyl chloride,2-phenyl-4-isononanoyl-5-methyl-(3H)-pyrazol-3-one is obtained with ayield of 75%. This compound distils at 165° C. under 0.1 Pa. The NMRspectrum recorded in CDCl₃ with TMS as reference exhibits the peaks:

0.9-1.4 ppm (m); 2.5 ppm (s); 2.6-2.8 ppm (m); 7.2-8.1 ppm (m); 13.5 ppm(s).

EXAMPLE 20

Preparation ofdi-1,6-(2-phenyl-5-methyl-4-pyrazolyl-3-one)-hexane-1,6-dione.

0.225 moles (39.15 g) of 2-phenyl-5-methyl-pyrazol-3-one are dissolvedin 250 cm³ dioxan. 0.4 moles (29.6 g) Ca(OH)₂ are added and then quickly0.1 moles (18.3 g) adipoyl chloride ClCO(CH₂)₄ COCl are added. Themixture is refluxed for 3/4 hour.

The reaction mixture is poured into 1.2 liters 2N hydrochloric acid. Thesolid product which precipitates is separated and redissolved inmethylene chloride. The organic solution is dried over magnesiumsulphate and then evaporated. A solid product is obtained with meltingpoint 203° C. whose mass spectrum shows a peak (M+1) at 459.

EXAMPLE 21

Preparation of 2-phenyl-4-oleoyl-5-phenyl-(3H)-pyrazol-3-one.

0.2 moles, i.e. 47.2 g 2-phenyl-5-phenyl-pyrazol-3-one are dissolved in600 cm³ dioxan at 60° C. 0.4 moles (29.6 g) lime are added and then for30 minutes, 0.2 moles oleoyl chloride. The temperature of the reactionmixture is raised to 95° C. and it is left under stirring for 2 hours.

The cooled mixture is poured into 1 liter hydrochloric acid (2N). An oilseparates out and is redissolved by methylene chloride. This organicphase is dried and then the solvent removed under vacuum.

An oily product is recovered with a yield of 84.5%. Purification hasbeen carried out by isolating the cobalt complex of theoleoylpyrazolone.

50 g of impure derivative, i.e. 0.1 moles are mixed in 100cm³ methanolwith 0.055 moles anhydrous cobalt acetate, i.e. 9.73 g. The mixture isrefluxed for 30 minutes.

The cobalt salt of the oleoylpyrazolone precipitates in methanol. It isfiltered and washed in water.

The salt is placed in methylene chloride and sulphuric acid (3N) isadded while stirring so as to destroy the cobalt complex and liberatethe oleoylpyrazolone which is then solubilised in methylene chloride.

This organic phase is separated, washed in water, dried and the solventremoved under reduced pressure.

The oil obtained corresponds to the pure oleoylpyrazolone, identified byNMR (triplet of ethylene protons between 5.2 and 5.5 ppm).

EXAMPLE 22

Preparation of 2-phenyl-4-undecenoyl-5-methyl-(3H)-pyrazol-3-one.

Following the procedure of example 18 with the same proportions butreplacing 2-ethylhexanoyl chloride by undecenoyl chloride, a solidderivative is obtained which after recrystallisation in hexane has amelting point of 40° C.

The following peaks are identified in the NMR spectrum using CDCl₃ asthe solvent and TMS as reference:

1 singlet at 2.5 ppm corresponding to the methyl at position 5 on thepyrazole ring;

1 triplet between 2.6 and 2.9 ppm corresponding to the methylene protonsin the α position to the carbonyl group;

1 doublet between 1.9 and 2.1 ppm attributed to the methylene protons inthe α position to the double bond;

multiplets between 0.9 and 2.4 ppm corresponding to the remainingprotons of the alkyl chain;

multiplets between 4.8 and 6.1 ppm attributed to the protons of thedouble bond;

multiplets between 7.1 and 8 ppm of the aromatic protons;

a 14.5 ppm singlet originating from the enol proton.

EXAMPLE 23

Preparation of thedi-1,10-(2-phenyl-5-phenyl-4-pyrazolyl-3-one)-decan-1,10-dione.

0.2 moles i.e. 47.2 g of 2-phenyl-5-phenyl-pyrazol-3-one are dissolvedin 600 cm³ dioxan at 60° C. 0.4 moles (29.6 g) lime Ca(OH)₂ are addedand then for 30 minutes 0.09 moles (21.5 g) sebacoyl chloride. Thetemperature of the mixture reaches 95° C. and this temperature is keptthere for 2 hours.

After cooling, the reaction mixture is poured into 1 liter hydrochloricacid (2N). The precipitated solid is redissolved in 200 cm³ methylenechloride.

The organic solution is washed twice with 200 cm³ H₂ SO₄ (3N) and thenwith distilled water. It is then dried and the solvent removed underreduced pressure.

The solid product obtained with a yield of 49.3% has a melting point of168° C. and has an NMR spectrum in agreement with the formula of thecompound.

EXAMPLE 24

Preparation of 2-phenyl-4-lauroyl-5-phenyl-(3H)-pyrazol-3-one.

Followng the procedure of example 18 with the same proportions butreplacing 2-phenyl-5-methyl-(3H)-pyrazol-3-one by2-phenyl-5-phenyl-(3H)-pyrazol-3-one (MW=136.3 g; mp=136° C.) and2-ethylhexanoyl chloride by lauroyl chloride a solid product is obtainedwhich after recrystallisation in hexane has a melting point of 69° C.

The product was identified by NMR.

The purity was checked by elementary analysis.

    ______________________________________                                                     Theory                                                                              Found                                                      ______________________________________                                        C %            77.51   76.4                                                   H %            8.13    8.2                                                    N %            6.7     6.75                                                   ______________________________________                                    

EXAMPLE 25

Preparation of 2-phenyl-4-(lauroyl)-5-propyl-(3H)-pyrazol-3-one.

Following the procedure of example 18 with the same proportions butreplacing 2-phenyl-5-methyl-(3H)-pyrazol-3-one by2-phenyl-5-propyl-(3H)-pyrazol-3-one (MW=202; mp=114°) and2-ethylhexanoyl chloride by lauroyl chloride a solid product is obtainedwhich after recrystallisation in hexane has a melting point of 61° C.

The NMR spectrum recorded in CDCl₃ with TMS as reference exhibitscharacteristic peaks for 2-phenyl-4-lauroyl-5-propyl-(3H)-pyrazol-3-one:

0.7-2.8 ppm (multiplets of the CH₃ and CH₂ groups)

7.2-8.1 ppm (multiplets of the aromatic protons)

14.5 ppm (singlet of the enol proton).

EXAMPLE 26

Affinity of the 4-acyl-(3H)-pyrazol-3-ones for the Fe³⁺ cation.

All the 4-acyl-(3H)-pyrazol-3-ones have been studied following the sameprocedure:

An aqueous solution of ferric sulphate Fe₂ (SO₄)₃ with 7.5 g/l Fe³⁺ isadjusted to pH 2 by adding H₂ SO₄ if necessary under potentiometriccontrol.

This aqueous phase is put in contact with a solution of4-acyl-(3H)-pyrazol-3-one (0.2M in SOLVESSO 150 without nonylphenoladditive) for 15 minutes while shaking in a separating funnel. Theextraction is carried out volume by volume at ambient temperature.

The analysis is carried out by measuring the iron content by atomicabsorption in the aqueous and organic phases.

The results are collected together in table V. It was found that the4-acyl-(3H)-pyrazol-3-ones have a significant affinity for iron when R₁is an aliphatic chain or when ZR₃ is aromatic. The corresponding4-acylpyrazolones therefore do not allow selective extraction of copperwith respect to iron.

EXAMPLE 27

Extraction of copper and iron by2-phenyl-4-thenoyl-5-methyl-(3H)-pyrazol-3-one.

The extraction is carried out as in example 17: a 0.14M solution of2-phenyl-4-thenoyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150 withoutnonylphenol is put in contact with an aqueous sulphuric acid solutioncontaining 3 g/l Cu²⁺ and 3 g/l iron (pH 2.5).

After analysing the copper and iron in the 2 phases the followingresults are obtained after 3 minutes of extraction:

Cu extracted: 71%

Fe extracted: 7.9%

[Cu]_(org) : [Fe]_(org) ≃9, i.e. a bad selectivity with respect to iron.

EXAMPLE 28

Extraction of copper and iron by2-(n-lauryl)-4-lauroyl-5-methyl-(3H)-pyrazol-3-one.

The extraction is carried out as in example No. 17: a 0.14M solution of2-(n-lauryl)-4-lauroyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150without nonylphenol as additive is put in contact with a sulphuric acidaqueous phase with 3 g/l Cu²⁺ and 3 g/l iron (pH 2.5).

After analysing the copper and iron in the 2 phases by atomic absorptionthe results are the following after 60 minutes extraction:

Cu extracted: 48.8%

Fe extracted: 6.9%

[Cu]_(org) : [Fe]_(org) ≃7, i.e. a bad selectivity with respect to iron.

EXAMPLE 29

Extraction of copper and iron by2-phenyl-4-benzoyl-5-methyl-(3H)-pyrazol-3-one.

An organic phase containing 0.14M2-phenyl-4-benzoyl-5-methyl-(3H)-pyrazol-3-one in SOLVESSO 150 with 10%nonylphenol is shaken up in a separating funnel, volume by volume withan aqueous sulphuric acid phase at pH 2.5 containing 3 g/l copper Cu²⁺and 3 g/l iron. The shaking up takes 1/2 hour at ambient temperature.

A precipitate of the complex with copper appears immediately.

An analysis is made of the aqueous phases by atomic absorption. Theresults are as follows:

Cu extracted: 97%

Fe extracted: 40%

[Cu]_(org) : [Fe]_(org) ≃2.5, i.e. practically no selectivity withrespect to iron.

                                      TABLE I                                     __________________________________________________________________________    EFFECT OF EXTRACTANT CONCENTRATION AND                                        OF THE pH OF THE AQUEOUS PHASE ON                                             THE EXTRACTION OF COPPER AND IRON                                                     Extractant concentration                                              Initial 2-phenyl-4-lauroyl-5-methyl-(3H)--pyrazol-3-one                                                             LIX 64 N                                aqueous 50 g/l    100 g/l   150 g/l   15% (V/V) .136 g/l                      phase type A                                                                          final                                                                            % extracted                                                                          final                                                                            % extracted                                                                          final                                                                            % extracted                                                                          final                                                                            % extracted                          (dilute H.sub.2 SO.sub.4)                                                             pH Cu  Fe pH Cu  Fe pH Cu  Fe pH Cu  Fe                               __________________________________________________________________________    Cu: 2,9 g/l                                                                           0,8                                                                              46,5                                                                              ˜0                                                                         0,8                                                                              85,3                                                                              ˜0                                                                         0,8                                                                              95,9                                                                              ˜6                                                                         0,8                                                                              43,5                                                                              ˜0                         Fe: 3,2 g                                                                     pH: 1                                                                         Cu: 2,9 g/l                                                                           1,5                                                                              90,0                                                                              ˜0                                                                         1,4                                                                              99,7                                                                              ˜3                                                                         1,4                                                                              99,9                                                                              ˜6                                                                         1,4                                                                              91,2                                                                              ˜6                         Fe: 3,2 g/l                                                                   pH: 2,5                                                                       __________________________________________________________________________     ˜ means approximately                                                   The diluent used was:                                                         SOLVESSO 150 for the pyrazolone                                               the product called ESCAID 100 for the extractant of type LIX.            

                                      TABLE II                                    __________________________________________________________________________    Effect of the extractant concentration and pH of the aqueous phase on the     extraction of copper and the impurities: Fe, Co, Ni.                                   Extractant concentration                                             Initial  2-phenyl-4-lauroyl-5-methyl-(3H)--pyrazol-3-one                                                                        KELEX 100                   aqueous  50 g/l       100 g/l      150 g/l        15% (V.V) .143 g/l          phase type B                                                                           final                                                                            % extracted                                                                             final                                                                            % extracted                                                                             final                                                                            % extracted final                                                                            % extracted              (dilute H.sub.2 SO.sub.4)                                                              pH Cu Fe                                                                              Ni                                                                              CO pH Cu Fe                                                                              Ni                                                                              CO pH Cu Fe Ni CO pH Cu Fe                                                                              Ni                                                                               CO               __________________________________________________________________________    Cu: 22,6 g/l                                                                           0,9                                                                              13,5                                                                             0 0 0  0,8                                                                              34,5                                                                             0 0 0  0,8                                                                              56,6                                                                             17,6                                                                             16,7                                                                             11 0,7                                                                              40,7                                                                             7,9                                                                               0                                                                               0               Fe: 6,1 g/l                                                                   Ni: 19,2 g/l                                                                  Co: 0,8 g/l                                                                   pH 1                                                                          same concen-                                                                           1,5                                                                              18,2                                                                             0 --                                                                              -- 1,1                                                                              34,1                                                                             0 --                                                                              -- 0,9                                                                              54,9                                                                              2,1                                                                              1,6                                                                             2,5                                                                              1,1                                                                              45,3                                                                             4,8  2,7                                                                      3,7                   trations                                                                      pH 2                                                                          __________________________________________________________________________     SOLVESSO 150 was used as the diluent for pyrazolone and for KELEX 100.   

                  TABLE III                                                       ______________________________________                                                    Concentration in aqueous reextraction                                         solutions of 1N H.sub.2 SO.sub.4                                  Selectivity   Cu (g/l)     Fe (g/l)                                           ______________________________________                                        4-lauroyl-P   11,9         0,032                                              4-(2-ethylhexanoyl)-P                                                                       11,5         <0,010                                             LIX 64 N      13,8         0,310                                              ______________________________________                                         P = 2phenyl-5-methyl-(3H)--pyrazol3-one.                                      Initial aqueous solution, type A:                                             Cu 3 g/l                                                                      Fe 3 g/l and pH = 2.5                                                    

                                      TABLE IV                                    __________________________________________________________________________    Extraction of copper in the presence of iron by 4-acyl-(3H)pyrazol-3-ones      4-acyl-(3H)pyrazol-3-ones R.sub.1 R.sub.2 ZR.sub.3                                                      Copper extracted after 3 min10 min60                                                      Iron extracted after 3 min10 min60                                           min                                                                                        ##STR6##                                                                             ##STR7##            __________________________________________________________________________     ##STR8##                                                                              CH.sub.3                                                                              ##STR9## 69,4%                                                                             75,3%                                                                             --  0,2%                                                                              0,3%                                                                              1,7%                                                                              1013   251                   ##STR10##                                                                             CH.sub.3                                                                             .sub.n C.sub.11 H.sub.23                                                                83% 86,8%                                                                             86,8%                                                                             0,2%                                                                              0,3%                                                                              0,8%                                                                              2185   289                   ##STR11##                                                                             CH.sub.3                                                                             .sub.n C.sub.17 H.sub.35 *                                                              55% 70% 70% 0,2%                                                                              0,2%                                                                              --  1160   350                   ##STR12##                                                                              ##STR13##                                                                           (CH.sub.2).sub.7CH* CH(CH.sub.2).sub.7CH.sub.3                                          59,4%                                                                             76,8%                                                                             81,5%                                                                              0,05%                                                                            0,1%                                                                              0,2%                                                                              3300   768                   ##STR14##                                                                              ##STR15##                                                                           .sub.n C.sub.11 H.sub.23                                                                62,9%                                                                             72,2%                                                                             74,7%                                                                             0,3%                                                                              0,7%                                                                              2%   370   103                   ##STR16##                                                                             .sub.n C.sub.3 H.sub.7                                                               .sub.n C.sub.11 H.sub.23                                                                48,0%                                                                             66% --  0,3%                                                                              0,7%                                                                              --   285    94                   ##STR17##                                                                             CH.sub.3                                                                             .sub.n C.sub.11 H.sub.23 *                                                              42,6%                                                                             65,9%                                                                             88,9%                                                                              0,25%                                                                            1,7%                                                                              1,7%                                                                               111    39                  LIX 64 N                  78,5%                                                                             83,5%                                                                             --   1,25%                                                                             1,72%                                                                            --   290    48                  (ESCAID)                                                                      __________________________________________________________________________     *nonylphenol (10%)                                                            Initial aqueous solution: 3 g/l Cu  3 g/l Fe                             

                  TABLE V                                                         ______________________________________                                        Extraction of iron by itself                                                  contact time: 15 minutes                                                                           Iron extracted                                                                          mg      extrac-                                                               organic tion                                   R.sub.1 R.sub.2  ZR.sub.3      phase   %                                      ______________________________________                                         ##STR18##                                                                            CH.sub.3 .sub.n C.sub.11 H.sub.23                                                                    155 mg    2%                                   .sub.n C.sub.12 H.sub.25                                                              CH.sub.3 .sub.n C.sub.11 H.sub.23                                                                    648 mg  8,6%                                    ##STR19##                                                                            C.sub.3 H.sub.7                                                                        .sub.n C.sub.11 H.sub.23                                                                    174 mg  2,3%                                    ##STR20##                                                                             ##STR21##                                                                             .sub.n C.sub.11 H.sub.23                                                                    132 mg  1,8%                                    ##STR22##                                                                            CH.sub.3                                                                                ##STR23##    121 mg  1,6%                                    ##STR24##                                                                            CH.sub.3 .sub.n C.sub.17 H.sub.35                                                                    207 mg  2,7%                                    ##STR25##                                                                            CH.sub.3                                                                                ##STR26##    648 mg  8,6%                                    ##STR27##                                                                            CH.sub.3                                                                                ##STR28##    2205 mg 29,4%                                  ______________________________________                                         Initial aqueous solution:                                                     7.5 g/l Fe                                                                     pH 2                                                                    

We claim:
 1. A 2-phenyl-4-acyl-pyrazol-3-one which is:(1)1,6-di(2-phenyl-5-methyl-4-pyrazolyl-3-one)-hexan-1,6-dione; (2)2-phenyl-4-undecenoyl-5-methyl-(3H)-pyrazol-3-one; (3)2-phenyl-4-oleoyl-5-phenyl-(3H)-pyrazol-3-one; or (4)1,10-di(2-phenyl-5-phenyl-4-pyrazolyl-3-one)-decan-1,10-dione.